Field of the Invention
The present invention relates to a power semiconductor module and a cooling element for holding the power semiconductor module.
It is known to attach power semiconductor modules, in particular those for electric drives, to a cooling element by screws or clamps. The electronic components of the power semiconductor modules are surrounded here by a housing which is usually composed of a thermoplast and which is usually of a rectangular configuration. In order to attach the module, the housing is attached to the cooling element by screws or clamps. The connection which is formed by the respective type of attachment between the power semiconductor module and the cooling element must be so secure here that satisfactory thermal contact between the housing and the cooling element is established in order to ensure that heat is satisfactorily conducted away. In particular the attachment of the housing by screws, by which it is possible to realize good thermal contact between the housing and the cooling element, is complex in terms of fabrication technology and is therefore costly. The use of clamps for attaching the module permits rapid mounting but produces a less precise connection between the module and the cooling element.
It is accordingly an object of the invention to provide a power semiconductor module and a cooling element for holding the power semiconductor module which overcomes the above-mentioned disadvantages of the prior art devices of this general type, which can easily be attached to the cooling element and with which a satisfactory thermal connection between a housing of the power semiconductor module and the cooling element is ensured.
With the foregoing and other objects in view there is provided, in accordance with the invention, a power semiconductor module. The module contains a housing having an underside and an upper side; and at least one spring element projecting from the upper side and disposed on the upper side.
The module can be inserted into a cut-out of the cooling element provided for that purpose. The spring element which projects from the upper side of the module serves to clamp the module between an upper face and a lower face of the cut-out in the cooling element, in order to bring about good thermal contact between the module and the cooling element.
According to one embodiment of the invention, there is provision for the housing of the power semiconductor module to have at least two spring elements, one of which is disposed in the region of a first edge of the upper side and one in the region of a second edge of the upper side. Such a module can be inserted into a T-shaped groove of the cooling element that is provided for that purpose, the module being secured to the lateral cut-outs on both sides of such a T-shaped groove by the spring elements. Two spring elements are preferably formed in the region of each of the edges.
In a further embodiment of the invention, there is provision for the spring elements to be formed integrally onto the housing. The spring elements are then composed, as is the housing, of a material that is a good thermal conductor, in particular a thermoplast. This embodiment of the invention permits, on the one hand, a particularly satisfactory thermal contact between the spring elements and the rest of the housing, as a result of which the spring elements can also contribute to conducting away heat from the housing to the cooling element. On the other hand, a housing can be manufactured using an injection-molding method with integrally molded-on spring elements so that, compared with manufacturing the housing, no additional method steps are necessary to manufacture the spring elements.
The spring elements are each formed in an arcuate shape with a first end and a second end. The first ends are connected to the upper side of the housing and the second ends are disposed spaced apart from the upper side in a spring-mounted manner.
The housing of the power semiconductor module preferably has shoulders in the region of the edges, as a result of which an upper face and two lower faces of the upper side are formed. In this embodiment, the spring elements are disposed on the lower faces of the upper side in the region of the edges.
In order to ensure lateral stability of the power semiconductor module according to the invention which is inserted into the groove of the cooling element, in one further embodiment of the invention, projections, with which the power semiconductor module can bear against the cooling element, are provided on side faces which extend from the edges between the upper side and the underside of the housing.
A cooling element according to the invention for holding the power semiconductor module according to the invention preferably has a T-shaped groove formed in the body of the cooling element and into which the power semiconductor module can be inserted.
According to one embodiment, cooling ribs that enlarge the surface of the cooling element and thus bring about improved conduction of heat to the surroundings are formed on a surface of the cooling element facing away from the groove.
The cooling element is preferably manufactured from an extruded section, preferably composed of aluminum.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a power semiconductor module and a cooling element for holding the power semiconductor module, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.